Nioxin Pro Clinical's Hair Fall Defense Serum is a leave-on scalp treatment for thinning hair. Designed for daily use, it's clinically proven to increase hair anchorage with visible results in only 8 weeks, while thickening hair from the very first use. It's formulated with innovative ingredients including sandalore, caffeine, lauric acid and niacinamide. Together they work to stimulate and nourish the hair follicles to prolong the growth cycle and improve hair resistance for fuller-looking hair. This effective leave-on scalp treatment is the first time sandalore has been leveraged to stimulate hair follicles and improve hair anchorage. Via improved hair anchorage; average results in 8 weeks, in a double-blind clinical study with 120 panelists.